Line an 8×8-inch pan with parchment paper, leaving some overhang. Lightly butter the parchment and set aside.

In a heavy-bottomed saucepan, add fruit puree, sugar, corn syrup, and heavy cream. Stir over medium heat until the sugar has dissolved.

Attach a candy thermometer and let the mixture boil undisturbed until it reaches 240°F (soft-ball stage), about 15–20 minutes.

Remove from heat. Stir in butter, sea salt, and vanilla extract until smooth and fully combined.

Pour the caramel into the prepared pan and let it cool completely at room temperature, at least 4 hours or overnight.

Once set, lift out the caramel slab and slice into 36 squares with a buttered knife. Wrap each piece in wax paper.